1. Field of the Invention
The present invention pertains to selenium lamps. More particularly, the invention relates to electroded lamps containing a fill including selenium or selenium compounds.
2. Related Art
An example of an electroded lamp with a selenium fill is disclosed in U.S. Pat. No. 5,606,220, entitled VISIBLE LAMP INCLUDING SELENIUM OR SULFUR, and PCT Publication No. WO 92/08240, each of which is hereby incorporated by reference in its entirety.
The lifetime of an electroded lamp depends in substantial part on the useful life of its electrodes. During operation, the electrode material reacts with the fill material and may decompose. Also, due to high electrode temperatures, some electrode material may evaporate and become deposited on the lamp walls, thereby blackening the walls. If too much electrode material evaporates, the lamp may fail to operate at all.
These problems are particularly relevant to electroded lamps with a selenium fill because of the reactive nature of selenium at typical lamp operating conditions. An electroded selenium lamp using conventional electrode materials may have an extremely limited operating lifetime.